Metal rolling system



I o f 2 Sheet FRE0 HARDING powam F. H. POWELL METAL ROLLING SYSTEM IBNQIENTOR aqn HES ATTORNEYS March 18, 1969 Filed Jan. 26, 1967 March 18, 1969 POWELL 3,433,947

METAL ROLLING SYSTEM Filed Jan. 26, 1967 Sheet ,2 of

H IS ATTORNEYS I FRED HARDING POWELL United States Patent Ofice 3,433,047 Patented Mar. 18, 1969 8 Claims ABSTRACT OF THE DISCLOSURE A backed rolling mill (such as a 4-high mill) is disclosed in which the working rolls are driven and the backing up rolls are also driven, with provision for predeterminedly controlling, preferably by an electric control system, the proportions of the total power or driving torque imparted to the working rolls and the backing up rolls respectively. The mill is adapted to compress and consolidate metal particles into a strip, which requires the application of exceptionally high power to the working rolls, which must have relatively small diameter. The controlled division of power among the rolls makes it possible to impart as much power to the working rolls as possible through their necks, and the balance through the backing up rolls to the working rolls, for purposes of reducing concentrated stresses in the working rolls.

Cross-reference to related application The invention of this application is a continuation-in-part of my copending application, Ser. No. 534,469, filed Mar. 15, 1966-, and now Patent No. 3,354,502.

Background of the inv ntion While conventional mills for rolling metal strip can generally be used in rolling metal particles into solid strip, it has been found that consolidation of metal particles into strip in one pass through a rolling mill requires an unusually high amount of power to be applied to the single set of working rolls used for this purpose. The diameter of the working rolls must be relatively small to satisfy particle rolling requirements, and this limits the amount of power which can be applied directly through the necks of the working rolls without breaking them. As the width of the mill is increased for purposes of rolling wider strips from particles, the point is reached where the resultant increased power can no longer be supplied through the necks of the working rolls. The conventional alternative to driving working rolls through their necks is to drive them through rolling contact with the backing up rolls, or through tension on the strip emerging from the mill, or both. These alternatives are unsatisfactory for particle rolling purposes, because the hot as-compacted strip emerging from the mill is not strong enough in tension to help appreciably in driving the mill, and driving the working rolls of a wide mill entirely from the backing up rolls would introduce diflicult problems of bracing the working rolls against lateral bending or deflection without interferring with adequate inflow of metal particles to the roll nip.

Summary The invention solves the problem outlined above by providing a mill which has work rolls with strong neck drive connections to the working rolls and separate drive connections to the backing up rolls, and means for effecting a pre-determined division of power between the set of working rolls, on the one hand, and the set of backing up rolls, on the other hand, so that as much power as practicable can be supplied to the working rolls and the balance can be supplied through the backing up rolls, thus making it possible to supply the total necessary power to the working rolls without such an excess of power at the necks as to break the rolls, or such an excess of power from the backing up rolls as to require auxiliary lateral supporting means which would complicate the design of the particle feed system.

Other deta'tils, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof proceeds.

Descripti n of drawings The accompanying drawings show a present preferred embodiment of the invention in which FIGURE 1 is a diagram of a rolling mill in accordance with the invention showing the driving means for the working and backing up rolls, the hopper being omitted in this figure;

FIGURE 2 is a diagrammatic elevational view of a portion of the mill shown in FIGURE 1, this figure being confined to a diagrammatic showing of the working and backing up rolls, the hopper for feeding particles to the mill, the particles being fed and the strip produced, all shown in vertical cross-section parallel to the pass line of the mill; and

FIGURE 3 is an electrical diagram of a typical control system for the mill.

Description of present preferred embodiment Referring now more particularly to the drawings, there is shown a rolling mill comprising parallel working rolls 2 whose axes are in a common generally horizontal plane having cooperating working faces 3, each of the rolls 2 having at one end A a first neck portion 4 of relatively great diameter relatively remote from the working face 3 of the roll and at the opposite end B a second neck portion 5 of relatively small diameter relatively close to the working face 3 of the roll, the ends A of the respective rolls 2 extending in opposite directions from the working faces 3 of the rolls, the rolls being driven through the ends A thereof by driving motors M and M respectively through reducing gear drive units D and D respectively. The neck portions 4 are journaled in relatively large bearings 6 and the neck portions 5 are journaled in relatively small bearings 7.

A hopper 8 (FIGURE 2) is provided for feeding particles 9 to the nip N of the working rolls 2, where the particles are compressed and 'metallurgically bonded together into a solid strip 10. The particles are fed preferably downwardly, by gravity, in a free-flowing condition. The particles are preferably preheated to a temperature suitable for hot rolling the metal, and means (not shown) are provided for cooling the working faces of the rolls during the rolling operation.

Backing up rolls 11 are provided behind the working rolls 2 to press the working rolls against the particles 9 and minimize deformation of the working rolls. The mill shown is a 4-high mill oriented to have the pass line vertical. The strip 10 is delivered downwardly as shown in FIGURE 2 and is drawn off under tension past a guide roll 12. The degree of tension is limited by the strength of the strip and the power used in producing such tension is only a few percent of the power used to turn the rolls.

The bearings for the backing up rolls 11 are designated 13 and, as shown in FIGURE 1, are disposed nearer the pass line of the rolling mill than the bearings 6. The bearings 6 and 13 overlap along the pass line of the rolling mill. Likewise the bearings 6 and 7 overlap along the pass line of the rolling mill. The bearings 7 are small enough to be disposed alongside the bearings 13 as shown in FIGURE 1. The bearings 6 are disposed outwardly of both the bearings 7 and the bearings 13 and also outwardly of the ends of the rolls journaled in the bearings 7. All of the bearings may be slidably mounted in frames and biased by springs as known to those skilled in the art, but when the mill is horizontally oriented imbalance of gravitational forces on the roll necks and bearings is avoided.

The backing up rolls 11 are driven by motors M and M respectively through reducing gear drive units D and D respectively. Suitable universal joints are provided in the drive trains as shown in FIGURE 1.

The driving arrangement shown in FIGURE 1 provides for delivery of part of the driving power to the working rolls and part to the backing up rolls. Means are provided for predeterminedly controlling the proportions of the total power imparted to the working rolls and the backing up rolls respectively. Desirably as much as possible of the driving power is imparted through the necks of the working rolls, such power being limited by the capacity of the Working rolls to be driven through their necks without breaking. The operator will determine in any particular situation what portion of the driving power can be imparted to the necks of the working rolls and what remaining portion through the backing up rolls. In a wide strip mill (e.g., for 100" wide aluminum strip), nearly half of the total driving power may be imparted to the working rolls through their necks and the remainder through the backing up rolls.

Any convenient means can be used for distributing the total mill power among the working rolls and backing up rolls. A typical electrical system for this purpose is illustrated diagrammatically in FIGURE 3. As shown in that figure, the backing up roll motors M and M are connected in parallel to DC generator 14, while the working roll motors M and M are connected in parallel to DC generator 15. The generators 14 and 15 are driven from a common power shaft (not shown).

Field regulators 16 and 17 control the distribution of power from generators 14 and 15, respectively, by means of a Ward-Leonard circuit load balance regulator means 18, load balance shifting means 19, motor operated rheostat mill speed control 20, and summing points means 21 and 22 all connected as shown in FIGURE 3. The source of current is illustrated diagrammatically at 23.

At all times power supplied to the working rolls is substantially equally divided between them and power supplied to the backing up rolls is substantially equally divided between them. The division of total mill power, however, between the pair of working rolls on the one hand and the pair of backing up rolls on the other hand is regulated by adjustment of load balance shifting means 19. The ratio of the division of power by means 19 remains substantially constant for any given setting. The total amount of power supplied to all the rolls is regulated by control 20 which determines mill speed.

While a present preferred embodiment of the invention has been illustrated and described, the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims.

I claim:

1. A rolling mill having working rolls and backing up rolls in peripheral driving engagement with the working rolls, drive means connected directly to the working rolls, drive means connected directly to the backing up rolls, and control means connected with both said drive means, said control means controlling the ratio of power received by the working rolls directly from the first-mentioned drive means, on the one hand, and indirectly through the backing up rolls from the second mentioned drive means, on the other hand.

2. A rolling mill as claimed in claim 1 in Which the mill is a 4-high mill with the backing up rolls of larger diameter than the working rolls and the axes of all four rolls substantially coplanar.

3. A rolling mill as claimed in claim 1 in which the control means are adjustable to vary said ratio of power at the will of the operator.

4. A rolling mill as claimed in claim 1 in which the driving means include electric motors as their prime movers and the control means are electrically connected with the electric motors.

5. A rolling mill as claimed in claim 4 in which the mill comprises a pair of working rolls, a pair of backing up rolls and four electric motors, one connected to each of said rolls.

6. A rolling mill as claimed in claim 5 in which the control means include two direct current generators, one supplying current for operating the electric motors of the driving means for the working rolls and the other supplying current for operating the electric motors of the driving means for the backing up rolls, and means regulating the current supplied by the respective generators.

7. A rolling mill as claimed in claim 1 including means for feeding particles to the nip of the working rolls to consolidate the particles into strip.

8. A mill for rolling metal particles into strip, comprising a pair of working rolls having cooperating working faces, a pair of backing up rolls in peripheral driving engagement with said working faces of the working rolls and means to feed metal particles into the nip of the working rolls, each working roll having at one end a first neck portion relatively remote from the working face of the roll and at the opposite end a second neck portion relatively close to the working face of the roll, the first mentioned ends of the respective working rolls extending in opposite directions from the working faces of the rolls, bearings for the working rolls in which the first and second neck portions are journaled, bearings for the backing up rolls nearer the pass line of the rolling mill than the bearings for the first neck portions of the working rolls, a pair of motors each having direct driving connection with one of the first mentioned ends of the working rolls, a pair of motors each have direct driving connection to the backing up rolls, and control means connected to each of said motors and adjustable control the ratio of power received by the pair of working rolls directly from the first rnentioned pair of motors, on the one hand, and indirectly through the backing up rolls from the second mentioned pair of motors, on the other hand.

References Cited UNITED STATES PATENTS 2,904,829 9/1959 Heck 18-9 3,172,313 3/1965 Fox 72-241 CHARLES W. LANHAM, Primary Examiner.

B. I. MUSTAIKIS, Assistant Examiner.

US. Cl. X.R. 

